Climate-based cauliflower planting guide for Seattle, Washington
When to Plant Cauliflower in Seattle: Timing and Maturity Guide
Cauliflower is usually well within the local season in Seattle. The practical questions are more about crop quality and harvest goals than about racing to maturity.
Typical Planting Window
Use the planting dates below for cauliflower in Seattle.
Gardeners usually start indoors around January 30 and plant outdoors from about February 27. Most varieties need about 65–85 days to reach maturity once they are in the garden.
Cauliflower usually performs comfortably in Seattle. Gardeners get the most from this climate when they use the margin to improve finish quality rather than merely count on maturity.
What the local margin changes most is that gardeners can hold out for a better-sized, better-finished crop instead of cutting early just to stay on schedule.
Best local strategy: Plant on time, protect uninterrupted growth, and harvest at the stage you actually want rather than leaving quality in the field.
Can Cauliflower Mature in Seattle?
Growing degree days measure how much useful warmth typically accumulates during the season. For cauliflower, this helps estimate whether local heat accumulation is usually enough for the crop to reach maturity on time.
From the usual planting window, Seattle typically provides about 4722 growing degree days for cauliflower. With a typical crop target of 1000, that leaves a heat margin of +3722. That large heat margin means the crop usually has no trouble reaching maturity here. In practice, planting timing mostly affects how comfortably the crop sizes up and when harvest is ready, not whether the crop can finish.
GDD Checkpoints for Seattle
If planting later than usual, this table shows how much growing degree day heat is still available from each point in the season. For cauliflower, it is most useful for judging how much freedom you still have to plant for quality, finish, and harvest goals as the season moves along.
| Checkpoint | Remaining GDD | Heat margin | Fit vs typical target |
|---|---|---|---|
| Apr 15 | 4513 | +3513 | Comfortable |
| May 1 | 4305 | +3305 | Comfortable |
| May 15 | 4077 | +3077 | Comfortable |
| Jun 1 | 3750 | +2750 | Comfortable |
| Jun 15 | 3451 | +2451 | Comfortable |
| Jul 1 | 3072 | +2072 | Comfortable |
Best Cauliflower Varieties for Seattle
In Seattle, early and mid-season cauliflower varieties are usually the best fit in a typical year. Slower choices can still work when gardeners want their specific qualities and do not give away margin through delay.
Varieties that often fit well here include:
- Snowball — a classic early cauliflower with reasonable reliability
- Amazing — productive but sensitive to timing and conditions
| Variety class | Typical days to maturity | Typical GDD need | Local fit |
|---|---|---|---|
| Early | 60–70 | 900 | Good fit |
| Mid-season | 70–85 | 1000 | Good fit |
Main risk: The most common issue here is not climate but management: uneven growth, delayed planting, or harvesting outside the best quality window.
How Frost Affects Cauliflower in Seattle
Seattle usually has about 249 frost-free days, with a typical last spring frost around March 13 and a typical first fall frost around November 17.
Cauliflower is generally lightly frost tolerant and temperatures below about 28°F ( -2 °C) can slow growth or damage plants.
Cauliflower is usually tolerant enough of cool conditions that light frost is not the main concern. The more useful question is how early planting affects establishment and overall crop quality.
Setbacks here usually come from practical decisions rather than from season length: planting later than ideal, uneven growth, poor moisture management, or harvesting outside the best eating window.
In Seattle, cauliflower already has plenty of seasonal room when planted around March 6. Local gardens do not all warm and cool at the same pace. In practical terms, the best spots are usually south-facing walls, sheltered gardens, raised beds, and sunnier urban lots. Cooler spots like low spots, exposed sites, and shadier yards are more likely to stay cooler and be less forgiving. For cauliflower, warmer local sites usually help the crop get established earlier and grow a little more steadily.
Related crops
Related crops worth comparing for the same city:
For a broader local overview, see the Seattle planting guide. You can also use the Growing Degree Day Planner to test planting dates and crop timing.